.zero {
  border: solid 1px;
  height: 500px;
}

.one {
  background-color: #03A9F4;
}

.two {
  background-color: #8bc34a;

  .two_one {
    background-color: #00897b;
  }
  .two_two {
    background-color: aqua;
  }
  .two_three {
    background-color: aquamarine;
  }
}

.three {
  background-color: #8e24aa;
}
